Hollow bursting charge

ABSTRACT

The primer ignites the adjacent conically shaped shell of ignition transmitting explosive, which in turn annularly ignites the main explosive charge, which main explosive charge has two axially extending conical recesses pointed towards each other, the rear of which receives therein the forward conical surface of an inert element that has a rearwardly extending conical surface received within the ignition transmitting shell. A conically shaped shell bottom piece may be provided around the ignition transmitting explosive with a complementary type fit and a transverse loose fit with the interior rear conical surface of the jacket, or the interior conical surface of the jacket may receive the complementary exterior surface of the ignition transmitting shell directly.

UnIted States Patent [151 3,6 Bucklisch [4 1 Apr. 25, 1972 [541 HOLLOWBURSTING CHARGE FOREIGN PATENTS 0R APPLICATIONS [72] Inventor: LudwigBucklisch, Rhondorf, Germany 714,747 9/1954 Great Britain ..l02/24 HC[73] Assignee: Dynam Nobel Akuengesenschafl 970,395 9/1964 Great Britain102/24 HC Trolsdorf Germany Primary ExaminerVerlin R. Pendegrass Filed!1969 Attorney-Craig, Antonelli & Hill 4 PP 80 I852 57 ABSTRACT [30]Foreign Application Priority Data 'Ijhe primerignites the adjacent coically shaped shell of ignitIon transmitting explosive, whIch In turnannularly Ignites the Mar, 3, 1968 Germany up 16 96 660-2 main explosivecharge, which main explosive charge has two axially extending conicalrecesses pointed towards each other, [52] U.S. Cl ..102/24 HC, 102/56the rear of which receives therein the forward Conical Surface [51] I1/02 of an inert element that has a rearwardly extending conical [58]Field Of SCII'Ch 102/24 HC, 56 Surface received within the ignitiontransmitting She A mcally shaped shell bottom piece may be providedaround the [56] References Cited ignition transmitting explosive with acomplementary type fit UNITED STATES PATENTS and a transverse loose fitwith the interior rear conical surface of the acket, or the interlorconical surface of the acket may 2, 1957 102/24 HC receive thecomplementary exterior surface of the ignition ,02 ,83 96 102/24 HCtransmitting shell directly. 3,034,393 5/1962 ...lO2/24 HC 3,45 l ,3 396/ l 969 Precoul 102/24 HC 4 Claims, 2 Drawing Figures PATENTED APR 2 51972 FIG. I

INVENTOR LUDWIG BUCKLISCH W 1711M I ATTORNEYS HOLLOW BURSTING CHARGEBACKGROUND OF THE INVENTION With axially symmetrical hollow burstingcharges having a primer in the center of the rear, ignition will bepropagated in a point-like manner at the point of ignition and fromthere the detonation is propagated in accordance with the distributionof the bursting charge. A more favorable ignition progression isattained by providing an areal or annular zone of ignition for the mainbursting charge; this is done by serially interposing an ignitiontransmitting charge between the primer and the main bursting charge, toannularly ignite the main bursting charge. If a conical insert isprovided in the front face of the hollow bursting charge with anaperture angle of about 60 to 120, the detonation waves willadvantageously impinge on the insert with a steep angle.

In order to obtain an annular ignition zone for the main burstingcharge, it is known to arrange a disk-shaped inert body between theprimer and the bursting main charge, which inert body consists of asubstance having a relatively low sound velocity, for example, syntheticmaterial, plaster of Paris, or the like, which will delay the directignition in the axial direction so that ignition will first of all takeplace radially of the main bursting charge after detouring the inertbody. Thereby, an annular ignition distribution of the main burstingcharge is obtained, and by appropriately shaping the inert body, theangle of impingement of the detonation front with respect to the mainbursting charge may be influenced.

With a hollow bursting charge of the above type, it is proved to bequite difficult to manufacture so that predictable uniformcharacteristics may be obtained. It has been found that only minorassymmetries of the elements of the explosive charge with respect to thecenter line will perceptively impair the efficiency of the hollowbursting charge. In order to obtain a uniform, good formation of thehollow charge flash or jet, the position of the explosive charge withrespect to the casing or jacket is of considerable importance in theaxial as well as the radial directions. Great efforts have been expendedin order to obtain a high degree of accuracy during the manufacture ofthe individual parts and during the assembly of the hollow burstingcharge. This expenditure necessary for the production, as well as thegreat number of rejects unavoidable, in particular during themanufacture of specially formed charges, is the cause for theconventional hollow explosive charges being rather undesirable in manyrespects.

SUMMARY OF THE INVENTION It is an object of the present invention toprovide a hollow explosive charge so that the detonation waves willimpinge on the main explosive charge and conical insert at a favorableangle, which charge may be manufactured and assembled with a relativelylow expenditure of money and material. This is accomplished, inaccordance with the invention, by assembling all the explosives in onejacket together with an inert element and a conical insert and conicallyoffsetting the jacket encompassing the hollow explosive charge on itsinterior toward the primer for reception of the conical shell, ignitiontransmitting explosive contacting the primer at preferably its flattenedtip. The inert body is provided as a double cone received within theinner conical surface of the ignition transmitting shell and a conicalbore in the main bursting charge, respectively. In this manner, theinert body may be maintained in a centered position within the jacket,if necessary, during the assembly process with respect to the primer bymeans of a suitable device. All of the conical surfaces of the explosiveelements have axes that are congruent.

Due to the conical shape of the various structural components, ageometrically simple and accurate centering is provided in the directionof the axis of the device during the assembly step, and at the sametime, the objective is achieved that the surfaces of two adjacentelements are exactly congruent. The advantages of the annulardistribution of the ignition for the main explosive charge are exploitedto their fullest extent, and it is thus accomplished that the hollowexplosive charge of the present invention has good detonating propertiesand can be manufactured on a large scale in an expensive and simplemanner for the first time.

With respect to the manufacturing, it may be impossible or impracticalto provide exactly complementary conical surfaces for the inside surfaceof the jacket and the outer conical surface of the ignition transmittingexplosive shell or it may be desirable to provide for compensation forassymmetries that cannot be eliminated by other means. For thesepurposes, in accordance with a further development of the presentinvention, a conical shell bottom section may be provided with a conicalexterior surface received within the conical end of the jacket and aconical interior surface receiving therein the ignition transmittingshell. The outside conical surface of the bottom piece will preferablyhave substantial play in the transverse direction with respect to thejacket but have a tight fit for its internal surface with respect to theignition transmitting explosive shell.

During the production of any two mutually complementary cones, it ispreferable to employ tools that have been manufactured on the samemachine tool, with the identical adjustments of the machining devices.

BRIEF DESCRIPTION OF THE DRAWING Further objects, features andadvantages of the present invention will become more clear from thefollowing detailed description of the drawing, wherein:

FIG. 1 is an axial cross-sectional view taken through a hollow explosivecharge according to the present invention; and

FIG. 2 is an axial cross-sectional view taken through another embodimentof the present invention.

DETAILED DESCRIPTION OF THE DRAWING As shown in FIG. 1, the hollowexplosive charge has a slightly conical tubular jacket or casing 8provided at one end with an inclined jacket bottom 2 having a conicalinterior surface and terminating in a rear portion receiving therein theprimer 6. The primer 6 is immediately adjacent to and ignites theconical shell ignition transmitting explosive l, which is slightlytruncated at its tip adjacent primer 6. The outer conical surface of theshell 1 is accurately complementary to the interior surface of thebottom 2 and has its interior conical surface accurately complementaryto the exterior adjacent conical surface of the inert element or body 3,which is shaped as a double cone with or without truncated front or rearends. The inert body 3 may be constructed of metal, synthetic material,plaster of Paris, or the like, and the cone thereof directed to thefront fits into a corresponding internal conical surface of the mainexplosive or bursting charge 4. The ignition transmitting explosive 1contacts the main explosive charge 4 along a surface that is anextension of the rearward conical surface of the inert body 3.

The jacket 8 may be made of metal and is provided with a conical insert5 extending within the complementary-formed conical bore of the mainexplosive charge 4 on the end opposite the rear primer 6. The detonationwaves will thus be propagated from the primer 6 by way of the ignitiontransmitting element 1 to the main explosive charge 4, with the inertbody being circumvented. Within the inert body 3, the waves willpropagate so slowly that they arrive with a delay at the main explosivecharge in order to continue the detonation in the axial direction. Thedetonation waves thus impinge on the conical insert 5 with a steepangle. As shown in FIG. 2, the second embodiment of the presentinvention employs a jacket 8 having a slightly conical taper on itsexterior to the primer 6. As in the embodiment described with respect toFIG. 1, the inert body 3 is shaped as a double cone and is enveloped, onthe one hand, by the main explosive charge 4, and on the other hand, bythe ignition transmitting explosive l, which is shell shaped. The outerconical surface of the ignition transmitting explosive 1 does notdirectly contact the bottom 2 of the jacket 8, but instead extends at alarger angle with a space therebetween. The space is filled by a bottompiece 7, which rests, on the one hand, on the internal surface of thejacket 8 and, on the other hand, complementarily engages the outersurface of the ignition transmitting explosive 1. In order to obtain asatisfactory detonating process, it is essential that the ignitiontransmitting explosive l, the inert body 3 and the explosive charge 4fit very accurately with respect to each other; the bottom piece 7 neednot contact the jacket 2 in an accurately fitting manner; rather, thisbottom piece 7 may be provided with transverse play with respect to thejacket 8 to compensate for assymmetries of the individual explosive andinert parts with respect to one another.

The manufacture of the identical conical shapes for interfitting conicalsurfaces may be suitably accomplished with tools, for example, pressingdies and drawing tools, of corresponding conical shape, which tools willbe produced on the same machine tool with the same setting for themachining operations, so that any unevenness which might occur iscompensated for during the assembly of the mating parts.

Although two embodiments have been specifically described and shown inthe attached drawing, for purposes of illustration, further embodiments,variations and changes are contemplated.

It is claimed:

1. An axially symmetrical explosive device with annular ignitioncomprising: a rear primer, a main explosive charge having conicallyshaped front and rear recesses disposed in an axially symmetrical mannerand pointed toward each other, the rear recess covering only a centralportion of the rear of said main charge, the peripheral region of saidmain explosive charge surrounding said rear recess having afrusto-conical surface tapered in the rearward direction; a conicalinsert in the front recess of said main explosive charge; a jacketsurrounding said main explosive charge and having a conically shapedinterior surface pointing rearwardly to said primer; an ignitiontransmitting explosive within said conically shaped interior surface ofsaid jacket and having the shape of a conical shell with its rear tipadjacent said primer and its front periphery complementary to andreceivable on the remaining peripheral region of said main explosivecharge; an inert body having oppositely pointed first and second conicalexterior surfaces, said first surface being complementary to andreceived within the conical surface of said ignition transmittingexplosive and the second surface complementary to and received withinthe rear conical recess in the main explosive charge whereby the axes ofall said conical surfaces are congruent with the main axis of the deviceby the provision of exclusively conical contact surfaces on the mainexplosive charges, the insert, the jacket, the ignition transmittingexplosive and the inert body.

2. The explosive device according to claim 1, including a conical shellbottom piece mounted between and complementary to each of the conicalshaped interior surface of said jacket with transverse play and theconical exterior surface of said ignition transmitting explosive withoutplay.

3. The device according to claim 1, wherein said ignition transmittingexplosive shell is frusto-conical on its exterior.

4. The device according to claim 3, wherein the interior surface of saidignition transmitting shell is frusto-conical and the complementaryexterior surface of said inert body is frustoconical.

1. An axially symmetrical explosive device with annular ignitioncomprising: a rear primer, a main explosive charge having conicallyshaped front and rear recesses disposed in an axially symmetrical mannerand pointed toward each other, the rear recess covering only a centralportion of the rear of said main charge, the peripheral region of saidmain explosive charge surrounding said rear recess having afrusto-conical surface tapered in the rearward direction; a conicalinsert in the front recess of said main explosive charge; a jacketsurrounding said main explosive charge and having a conically shapedinterior surface pointing rearwardly to said primer; an ignitiontransmitting explosive within said conically shaped interior surface ofsaid jacket and having the shape of a conical shell with its rear tipadjacent said primer and its front periphery complementary to andreceivable on the remaining peripheral region of said main explosivecharge; an inert body having oppositely pointed fiRst and second conicalexterior surfaces, said first surface being complementary to andreceived within the conical surface of said ignition transmittingexplosive and the second surface complementary to and received withinthe rear conical recess in the main explosive charge whereby the axes ofall said conical surfaces are congruent with the main axis of the deviceby the provision of exclusively conical contact surfaces on the mainexplosive charges, the insert, the jacket, the ignition transmittingexplosive and the inert body.
 2. The explosive device according to claim1, including a conical shell bottom piece mounted between andcomplementary to each of the conical shaped interior surface of saidjacket with transverse play and the conical exterior surface of saidignition transmitting explosive without play.
 3. The device according toclaim 1, wherein said ignition transmitting explosive shell isfrusto-conical on its exterior.
 4. The device according to claim 3,wherein the interior surface of said ignition transmitting shell isfrusto-conical and the complementary exterior surface of said inert bodyis frusto-conical.